This invention relates to an emission computed tomograph.
Emission computed tomography commonly referred to as ECT is a technique for obtaining an image of the distribution of radioactivity of radioisotope within a desired plane perpendicular to the axis of the body of a patient being examined by administering to the patient a pharmaceutical compound labelled with the radioisotope, detecting from outside the body the radiation such as X-rays or gamma (.gamma.) radiation emitted by the isotope that has been accumulated in a region or organ of the body of the patient, and processing the detected data by an electronic computer.
Gamma radiation emitting radionuclides such as .sup.133 Xe, .sup.99m Tc and .sup.81m Kr or positron emitting radionuclides such as .sup.11 C, .sup.13 N and .sup.15 O are used as the radioisotope. Since the two types of radionuclides have different emission characteristics, it has been customary to design an apparatus for exclusive use with a particular kind of radionuclides, so that different types of apparatus must be used with different kinds of radionuclides. This certainly is inconvenient and uneconomical.
Accordingly, the primary object of the invention is to provide an emission computed tomograph which can be used with different kinds of radionuclides with a short conversion time.
Another object of the invention is to provide such an emission computed tomograph as aforesaid which is simple in construction with a relatively small number of movable component parts and therefore is reliable in operation.
Another object of the invention is to provide such a emission computed tomograph as aforesaid which requires a relatively short time for measurement.
The invention will be described in detail with reference to the accompanying drawing.